To realize the considerable clinical potential of interferons ("IFNs"), their the biological activity must be retained during storage and administration. However, the stability of IFNs has proven to be a greater problem than was appreciated from early observations on the stability of crude materials. J. Sedmak et al., "Procedures for Stabilization of Interferons", Methods in Enzymology, 78, p. 591 (1981). It is now realized that IFNs in solution can be inactivated by a variety of physical and chemical treatments, and that gamma interferons ("IFN-.gamma.s") are particularly pH- and heat-labile. J. Sedmak and S. Grossberg, "Stabilization of Interferons", Texas Reports on Biology and Medicine, 35, p. 198 (1977).
Although lyophilization in the presence of serum albumin is a standard stabilizing formulation of IFNs ("Procedures for Stabilization of Interferons", Methods of Enzymology, 78, pp. 593-94 (1981)), numerous other agents have been tested, including gelatin, tripeptides, sodium dodecyl sulfate and thioctic acid. J. Sedmak et al., "Thermal and Vortical Stability of Purified Human Fibroblast Interferon", Human Interferon Production and Clinical Use, pp. 133-52 (1978); P. Jameson et al., "Thermal Stability of Freeze-Dried Mammalian Interferons", Cryobiology 16, pp. 301-14 (1979).